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New book "The Hidden Logic of Sudoku"
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berthier

Joined: 13 Jun 2007
Posts: 43
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Location: Paris, France

Items
PostPosted: Thu Jun 14, 2007 8:22 am    Post subject: Reply with quote

gsf wrote:
only 3/19351 cause my solver to guess

I guess 19351 is the total number of puzzles solved by SudoRules in the 2 Sudogen collections.
What about the Royle17 collection?

gsf wrote:
here they are with berthier's level, SE rating and rating time:
Code:

07 8.3 5.00s 900020000000706200087100300000002000001500700590060000008000000140000050000849030
09 7.2 4.00s 400382000000050800900007000000008050002005740050090020240003080009270000006000400
10 8.5 2.00s 100060800008003001000020005060007000034800000002900703000400098000000000609070000


Could you precise from which of my 3 collections they come?
I don't have time now, but in a forthcoming post, I'll put my complete resolution paths for these 3 puzzles.

gsf wrote:

level 01 are consistently FNB (naked/hidden singles + box-line(locked candidates))
level 02 also have THW (naked/hidden tuples + x-wing/swordfish/jellyfish)
level 03 has some crossover with 02 + XYK (x-cycle + y-cycle + knots (contradiction chains))
but 03-10 seem to be a hodgepodge of XYK

For the definition of my levels, see my post on the Solving sudoku forum.

gsf wrote:
so I'd like to know the details of why one view (mine) of levels 03-10 seems to be random
while another (berthier's) is stratified into 8 layers

I don't know your solver, but my stratification is a mere consequence of my definitions of the levels.
In turn, this definition is justified by the facts that:
- no (first order) logical formula can define a chain of a given type but of undefined length (well, that's not strictly true, since you can always write a disjunction of formulæ for chains of all lengths upto 81 - taking into account the fact that I've proven that chains should have no loops - but who'd care writing such a formula?). I'm wondering if your solver does not rely on subsets and implicit (pseudo-) second order formulæ;
- rules of a given type and length are logically independent from simpler rules (i.e. rules of simpler types or shorter lengths).
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berthier

Joined: 13 Jun 2007
Posts: 43
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Location: Paris, France

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PostPosted: Thu Jun 14, 2007 1:33 pm    Post subject: Reply with quote

gsf wrote:

only 3/19351 cause my solver to guess
here they are with berthier's level, SE rating and rating time:
Code:

07 8.3 5.00s 900020000000706200087100300000002000001500700590060000008000000140000050000849030
09 7.2 4.00s 400382000000050800900007000000008050002005740050090020240003080009270000006000400
10 8.5 2.00s 100060800008003001000020005060007000034800000002900703000400098000000000609070000


As I promised earlier this morning, here are the full Sudorules solution paths for the three puzzles your solver cannot solve without T&E.
This is the listing from SudoRules, slightly hand edited to make it a little shorter. Elementary constraints propagtion rules are not displayed.
(The lines starting with arrows should be displaced to the right, but the software of this forum brings them to left side.)
Of course, conversely, I'd be very interested in having the detailed solutions for a few puzzles solved by your solver(s) and not by mine.


CLIPS> (defglobal ?*grids-file* = (str-cat ?*GridsDir* "gsf.txt"))

CLIPS> (solve-nth-grid-from-text-file ?*grids-file* 1)
***** SudoRules version 12 *****
900020000
000706200
087100300
000002000
001500700
590060000
008000000
140000050
000849030
number 2 : hidden-single-on-row R3 ==> R3C1 = 2
number 7 : hidden-single-on-row R6 ==> R6C6 = 7
number 3 : naked-single ==> R8C6 = 3
number 7 : naked-single ==> R8C5 = 7
number 1 : hidden-single-in-block B5 ==> R4C5 = 1
number 5 : naked-single ==> R7C5 = 5
number 9 : naked-single ==> R3C5 = 9
number 1 : naked-single ==> R7C6 = 1
number 9 : hidden-single-in-block B5 ==> R4C4 = 9
number 9 : hidden-single-on-column C3 ==> R8C3 = 9
number 9 : hidden-single-on-column C7 ==> R7C7 = 9
number 8 : row R6 interaction with block B6
==> 8 eliminated from the candidates for R5C9
==> 8 eliminated from the candidates for R5C8
==> 8 eliminated from the candidates for R4C9
==> 8 eliminated from the candidates for R4C8
==> 8 eliminated from the candidates for R4C7
number 8 : hidden-single-on-row R4 ==> R4C1 = 8
number 7 : hidden-single-in-block B4 ==> R4C2 = 7
number 6 : row R3 interaction with block B3
==> 6 eliminated from the candidates for R1C9
==> 6 eliminated from the candidates for R1C8
==> 6 eliminated from the candidates for R1C7
numbers 4 and 6 : naked-pairs-in-column C8: R3C8-R4C8
==> 6 eliminated from the candidates for R7C8
==> 4 eliminated from the candidates for R7C8
number 4 : hidden-single-in-block B9 ==> R7C9 = 4
numbers 4 and 6 : naked-pairs-in-column C8: R3C8-R4C8
==> 4 eliminated from the candidates for R6C8
==> 6 eliminated from the candidates for R5C8
==> 4 eliminated from the candidates for R5C8
==> 4 eliminated from the candidates for R2C8
number 4 : row R2 interaction with block B1
==> 4 eliminated from the candidates for R1C3
numbers 4 and 6 : naked-pairs-in-column C8: R3C8-R4C8
==> 4 eliminated from the candidates for R1C8
number 6 : xyzt5-chain-type-3 on cells R4C8*, R3C8, R3C9, R4C9* and R4C3* with numbers 6, 4, 6, 5 and 3
==> 6 eliminated from the candidates for R4C7
number 6 : column C7 interaction with block B9
==> 6 eliminated from the candidates for R9C9
==> 6 eliminated from the candidates for R8C9
column C9 : hxyt6-rn-chain on rn-cells R1N7*, R7N7, R7N3, R7N6, R8N6 and R8N8* with columns C9, C8, C1, C2, C4 and C7
==> C9 eliminated from the rn-candidates for R1N8
i.e. 8 eliminated from the candidates for R1C9
number 8 : xyzt7-chain-type-2 on cells R8C7*, R9C7, R6C7*, R6C4, R1C4, R3C6 and R1C6* with numbers 8, 6, 1, 4, 3, 4 and 5
==> 8 eliminated from the candidates for R1C7
number 8 : xyzt7-chain-type-3 on cells R8C9*, R7C8, R9C9, R6C9*, R6C4, R1C4 and R2C5* with numbers 8, 2, 7, 1, 3, 4 and 3
==> 8 eliminated from the candidates for R2C9
number 8 : block B3 interaction with column C8
==> 8 eliminated from the candidates for R6C8
column C3 : hxyt7-rn-chain on rn-cells R2N4*, R5N4, R5N8, R2N8, R2N9, R2N1 and R2N5* with columns C3, C1, C6, C5, C8, C9 and C2
==> C3 eliminated from the rn-candidates for R2N3
i.e. 3 eliminated from the candidates for R2C3
number 5 : xyzt6-chain-type-3 on cells R3C9*, R3C8, R4C8, R4C9, R4C3 and R2C3* with numbers 5, 6, 4, 6, 3 and 4
==> 5 eliminated from the candidates for R2C9
number 5 : row R2 interaction with block B1
==> 5 eliminated from the candidates for R1C3
==> 5 eliminated from the candidates for R1C2
number 6 : xy6-chain on cells R4C8*, R3C8, R3C9, R3C6, R1C4 and R1C3* with numbers 6, 4, 6, 5, 4 and 3
==> 6 eliminated from the candidates for R4C3
number 6 : row R4 interaction with block B6
==> 6 eliminated from the candidates for R5C9
column C2 : hxyt7-rn-chain on rn-cells R2N5*, R2N4, R5N4, R5N8, R2N8, R2N9 and R2N1* with columns C2, C3, C1, C6, C5, C8 and C9
==> C2 eliminated from the rn-candidates for R2N3
i.e. 3 eliminated from the candidates for R2C2
number 1 : xyt5-chain on cells R2C2*, R2C3, R4C3, R6C3 and R6C8* with numbers 1, 5, 4, 3 and 2
==> 1 eliminated from the candidates for R2C8
number 3 : xyt7-chain on cells R6C4*, R1C4, R1C3, R1C2, R2C2, R2C3 and R4C3* with numbers 3, 4, 3, 6, 1, 5 and 4
==> 3 eliminated from the candidates for R6C3
number 1 : xyzt7-chain-type-4 on cells R9C7*, R8C7, R8C9, R7C8, R1C8*, R2C8 and R2C9* with numbers 1, 6, 8, 2, 7, 8 and 9
==> 1 eliminated from the candidates for R1C7
numbers 4 and 5 : naked-pairs-in-column C7: R1C7-R4C7
==> 4 eliminated from the candidates for R6C7
number 4 : block B6 interaction with row R4
==> 4 eliminated from the candidates for R4C3
number 3 : naked-single ==> R4C3 = 3
number 6 : naked-single ==> R1C3 = 6
numbers 5 and 6 : naked-pairs-in-column C9: R3C9-R4C9
==> 5 eliminated from the candidates for R1C9
number 2 : xyz-wing on cells R5C2*, R9C2* and R9C3* with numbers 2, 6 and 5
==> 2 eliminated from the candidates for R7C2
number 2 : block B7 interaction with row R9
==> 2 eliminated from the candidates for R9C9
numbers 1 and 7 : naked-pairs-in-column C9: R1C9-R9C9
==> 1 eliminated from the candidates for R6C9
==> 1 eliminated from the candidates for R2C9
… (Naked Singles)…

GRID 1 SOLVED IN CONTEXT cont-0, AT DEPTH 0. MAX-DEPTH = 0. LEVEL = L7, TECHNIQUE = XYZT7
936428517
415736289
287195346
873912465
621584793
594367128
368251974
149673852
752849631




CLIPS> (solve-nth-grid-from-text-file ?*grids-file* 2)
***** SudoRules version 12 *****
400382000
000050800
900007000
000008050
002005740
050090020
240003080
009270000
006000400
number 1 : naked-single ==> R9C5 = 1
number 6 : naked-single ==> R7C5 = 6
number 4 : naked-single ==> R8C6 = 4
number 4 : naked-single ==> R3C5 = 4
number 3 : naked-single ==> R5C5 = 3
number 2 : naked-single ==> R4C5 = 2
number 9 : naked-single ==> R9C6 = 9
number 5 : naked-single ==> R7C4 = 5
number 8 : naked-single ==> R9C4 = 8
number 4 : hidden-single-on-row R2 ==> R2C9 = 4
number 2 : hidden-single-on-row R2 ==> R2C2 = 2
number 2 : hidden-single-on-row R9 ==> R9C9 = 2
number 2 : hidden-single-in-block B3 ==> R3C7 = 2
number 5 : hidden-single-on-row R9 ==> R9C1 = 5
number 9 : hidden-single-on-column C4 ==> R2C4 = 9
number 9 : hidden-single-on-column C8 ==> R1C8 = 9
numbers 1 and 6 : naked-pairs-in-block B5: R5C4-R6C6
==> 6 eliminated from the candidates for R6C4
==> 1 eliminated from the candidates for R6C4
==> 6 eliminated from the candidates for R4C4
==> 1 eliminated from the candidates for R4C4
number 7 : c4-chain row-col-bl on cells R9C2-R9C8-R2C8-R1C9
==> 7 eliminated from the candidates for R1C2
number 7 : x-wing-in-rows R1 and R7 with columns C3 and C9
==> 7 eliminated from the candidates for R6C3
==> 7 eliminated from the candidates for R4C3
==> 7 eliminated from the candidates for R2C3
number 3 : xy-wing on cells R9C2*, R7C3 and R2C3* with numbers 3, 7 and 1
==> 3 eliminated from the candidates for R3C2
number 3 : xyzt9-chain-type-3 on cells R2C3*, R7C3, R1C3, R3C3*, R3C2, R1C2, R1C7, R1C9 and R2C8* with numbers 3, 1, 7, 5, 8, 6, 1, 6 and 7
==> 3 eliminated from the candidates for R2C1
number 3 : block B1 interaction with column C3
==> 3 eliminated from the candidates for R6C3
==> 3 eliminated from the candidates for R4C3
row R2 : hxy7-cn-chain on cn-cells C8N7*, C2N7, C4N7, C4N4, C3N4, C3N8 and C3N3* with rows R2, R9, R4, R6, R4, R6 and R3
==> R2 eliminated from the cn-candidates for C8N3
i.e. 3 eliminated from the candidates for R2C8
number 3 : hidden-single-on-row R2 ==> R2C3 = 3
number 1 : xyzt9-chain-type-3 on cells R2C6*, R6C6, R5C4, R5C1*, R6C3, R4C3, R7C3, R9C2 and R8C1* with numbers 1, 6, 1, 6, 8, 4, 1, 7 and 3
==> 1 eliminated from the candidates for R2C1
number 1 : xyzt4-chain-type-2 on cells R1C2*, R2C1, R1C3* and R1C7* with numbers 1, 6, 7 and 5
==> 1 eliminated from the candidates for R1C9
number 7 : xyt8-chain on cells R2C1*, R2C6, R2C8, R9C8, R9C2, R7C3, R4C3 and R4C4* with numbers 7, 6, 1, 7, 3, 7, 1 and 4
==> 7 eliminated from the candidates for R4C1
number 3 : xyt9-chain on cells R9C2*, R7C3, R4C3, R6C3, R3C3, R1C3, R2C1, R5C1 and R4C1* with numbers 3, 7, 1, 4, 8, 5, 7, 6 and 1
==> 3 eliminated from the candidates for R8C1
number 3 : column C1 interaction with block B4
==> 3 eliminated from the candidates for R4C2
number 7 : xyt7-chain on cells R2C1*, R2C6, R6C6, R5C4, R5C1, R8C1 and R7C3* with numbers 7, 6, 1, 6, 1, 8 and 1
==> 7 eliminated from the candidates for R1C3
…(Naked Singles and Hidden Singles)…

GRID 2 SOLVED IN CONTEXT cont-0, AT DEPTH 0. MAX-DEPTH = 0. LEVEL = L9, TECHNIQUE = XYZT9
415382697
723956814
968147235
371428956
892635741
654791328
247563189
189274563
536819472




CLIPS> (solve-nth-grid-from-text-file ?*grids-file* 3)
***** SudoRules version 12 *****
100060800
008003001
000020005
060007000
034800000
002900703
000400098
000000000
609070000
number 8 : hidden-single-on-column C5 ==> R8C5 = 8
number 8 : hidden-single-on-column C6 ==> R3C6 = 8
number 8 : hidden-single-on-row R9 ==> R9C2 = 8
number 1 : hidden-single-on-row R3 ==> R3C4 = 1
number 9 : hidden-single-on-row R8 ==> R8C6 = 9
number 9 : hidden-single-in-block B2 ==> R2C5 = 9
number 4 : hidden-single-in-block B2 ==> R1C6 = 4
number 6 : hidden-single-on-column C4 ==> R8C4 = 6
number 6 : hidden-single-in-block B9 ==> R7C7 = 6
number 6 : hidden-single-on-row R2 ==> R2C8 = 6
number 6 : hidden-single-on-row R3 ==> R3C3 = 6
number 6 : hidden-single-in-block B6 ==> R5C9 = 6
number 6 : hidden-single-on-column C6 ==> R6C6 = 6
number 7 : hidden-single-in-block B4 ==> R5C1 = 7
number 9 : hidden-single-on-row R5 ==> R5C7 = 9
number 9 : hidden-single-on-row R4 ==> R4C1 = 9
number 8 : hidden-single-on-column C1 ==> R6C1 = 8
number 8 : hidden-single-on-column C8 ==> R4C8 = 8
number 9 : hidden-single-on-row R3 ==> R3C2 = 9
number 7 : hidden-single-on-row R3 ==> R3C8 = 7
number 7 : hidden-single-on-column C9 ==> R8C9 = 7
number 9 : hidden-single-on-row R1 ==> R1C9 = 9
number 4 : row R9 interaction with block B9
==> 4 eliminated from the candidates for R8C8
==> 4 eliminated from the candidates for R8C7
number 4 : block B3 interaction with column C7
==> 4 eliminated from the candidates for R9C7
number 5 : block B2 interaction with column C4
==> 5 eliminated from the candidates for R9C4
number 4 : block B3 interaction with column C7
==> 4 eliminated from the candidates for R4C7
number 5 : block B2 interaction with column C4
==> 5 eliminated from the candidates for R4C4
number 2 : x-wing-in-columns C4 and C9 with rows R4 and R9
==> 2 eliminated from the candidates for R9C8
==> 2 eliminated from the candidates for R9C7
==> 2 eliminated from the candidates for R9C6
==> 2 eliminated from the candidates for R4C7
numbers 1 and 5 : naked-pairs-in-row R4: R4C3-R4C7
==> 5 eliminated from the candidates for R4C5
==> 1 eliminated from the candidates for R4C5
number 2 : c4-chain row-bl-col on cells R1C2-R1C8-R2C7-R8C7
==> 2 eliminated from the candidates for R8C2
number 5 : xyzt9-chain-type-1 on cells R9C6*, R7C6*, R5C6, R5C5, R5C8, R1C8, R3C7, R3C1 and R7C1* with numbers 5, 1, 2, 5, 1, 2, 3, 4 and 3
==> 5 eliminated from the candidates for R7C5
number 5 : column C5 interaction with block B5
==> 5 eliminated from the candidates for R5C6
number 3 : xyt9-chain on cells R7C5*, R9C6, R7C6, R5C6, R5C5, R5C8, R1C8, R3C7 and R3C1* with numbers 3, 1, 5, 2, 1, 5, 2, 3 and 4
==> 3 eliminated from the candidates for R7C1
number 3 : c4-chain col-row-bl on cells R8C1-R8C7-R3C7-R1C8
==> 3 eliminated from the candidates for R8C8
number 5 : xyzt8-chain-type-1 on cells R4C7*, R5C8*, R5C6, R9C6, R7C6, R9C4, R9C7 and R8C8* with numbers 5, 1, 2, 1, 5, 2, 3 and 1
==> 5 eliminated from the candidates for R6C8
number 3 : xyt10-chain on cells R7C5*, R9C6, R7C6, R7C1, R7C2, R7C3, R8C3, R4C3, R4C7 and R9C7* with numbers 3, 1, 5, 2, 5, 7, 3, 1, 5 and 1
==> 3 eliminated from the candidates for R9C4
number 2 : naked-single ==> R9C4 = 2
number 3 : naked-single ==> R4C4 = 3
number 4 : naked-single ==> R4C5 = 4
number 2 : naked-single ==> R4C9 = 2
number 4 : naked-single ==> R9C9 = 4
number 4 : hidden-single-on-column C8 ==> R6C8 = 4
number 2 : hidden-single-on-row R5 ==> R5C6 = 2
number 3 : hidden-single-on-column C5 ==> R7C5 = 3
number 2 : row R7 interaction with block B7
==> 2 eliminated from the candidates for R8C1
number 3 : row R9 interaction with block B9
==> 3 eliminated from the candidates for R8C7
number 1 : xyzt7-chain-type-3 on cells R4C3*, R4C7, R5C8, R8C8*, R1C8, R1C3 and R7C3* with numbers 1, 5, 1, 5, 2, 3 and 7
==> 1 eliminated from the candidates for R8C3
number 5 : xyt5-chain on cells R6C2*, R4C3, R8C3, R1C3 and R1C4* with numbers 5, 1, 5, 3 and 7
==> 5 eliminated from the candidates for R1C2
number 2 : xyt5-chain on cells R1C2*, R1C4, R1C3, R8C3 and R7C1* with numbers 2, 7, 5, 3 and 5
==> 2 eliminated from the candidates for R7C2
number 2 : hidden-single-on-row R7 ==> R7C1 = 2
number 5 : xyzt5-chain-type-3 on cells R6C2*, R4C3, R8C3, R8C1* and R8C2* with numbers 5, 1, 5, 3 and 4
==> 5 eliminated from the candidates for R7C2
number 1 : c6-chain on cells R9C6-R7C6-R7C3-R4C3-R4C7-R5C8
==> 1 eliminated from the candidates for R9C8
number 5 : xyz-wing on cells R9C8*, R9C7* and R4C7* with numbers 5, 3 and 1
==> 5 eliminated from the candidates for R8C7
number 1 : xy5-chain on cells R7C2*, R1C2, R1C8, R9C8 and R9C6* with numbers 1, 7, 2, 3 and 5
==> 1 eliminated from the candidates for R7C6
number 5 : naked-single ==> R7C6 = 5
number 1 : naked-single ==> R9C6 = 1
number 5 : row R9 interaction with block B9
==> 5 eliminated from the candidates for R8C8
number 1 : row R7 interaction with block B7
==> 1 eliminated from the candidates for R8C2
row R1 : hxy5-cn-chain on cn-cells C2N2*, C7N2, C7N1, C3N1 and C3N7* with rows R1, R2, R8, R4 and R7
==> R1 eliminated from the cn-candidates for C2N7
i.e. 7 eliminated from the candidates for R1C2
…(Naked Singles and Hidden Singles)…

GRID 3 SOLVED IN CONTEXT cont-0, AT DEPTH 0. MAX-DEPTH = 0. LEVEL = L10, TECHNIQUE = XYT10
125764839
478593261
396128475
961347582
734852916
852916743
217435698
543689127
689271354
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gsf

Joined: 18 Aug 2005
Posts: 408
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Location: NJ USA

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PostPosted: Thu Jun 14, 2007 2:18 pm    Post subject: Reply with quote

berthier wrote:
gsf wrote:
only 3/19351 cause my solver to guess

I guess 19351 is the total number of puzzles solved by SudoRules in the 2 Sudogen collections.
What about the Royle17 collection?

well, RedEd had asked for some info, from my solver, on puzzles you generated
gfroyle's puzzles have already been analyzed in much more depth, so I omitted them
Quote:

Could you precise from which of my 3 collections they come?

Code:

(c) fgrep -n -f p berth*.dat
berthier-10.dat:20:1...6.8....8..3..1....2...5.6...7....348.......29..7.3...4...98.........6.9.7....
berthier17-07.dat:138:9...2.......7.62...871..3.......2.....15..7..59..6......8......14.....5....849.3.
berthier17-09.dat:8:4..382.......5.8..9....7........8.5...2..574..5..9..2.24...3.8...927......6...4..

Quote:

For the definition of my levels, see my post on the Solving sudoku forum.

I did, thanks
gsf wrote:
so I'd like to know the details of why one view (mine) of levels 03-10 seems to be random
while another (berthier's) is stratified into 8 layers

Quote:

I don't know your solver, but my stratification is a mere consequence of my definitions of the levels.

so the straification of levels 03-10 is based on sizes of (in my solver) matched XYK structures
that answers my question
my default analysis just lumped 03-10 together into one bucket
Quote:

In turn, this definition is justified by the facts that:

we (you, me, most other (mechanical) solvers) have similar justifications
modulo constraint/rule order and matched structure granularity

also, since my solver went into guessing for the 3 puzzles above
a trace would not be as interesting as the pm grids where it fell into guessing
I'll look at that later today and post those sticking points,
hopefully with some insight based on your detailed traces
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berthier

Joined: 13 Jun 2007
Posts: 43
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PostPosted: Thu Jun 14, 2007 2:40 pm    Post subject: Reply with quote

[quote="gsf"]so the straification of levels 03-10 is based on sizes of (in my solver) matched XYK structures
[quote]
You mentionned several times XYK constraints (and BRNet), which I don't know. I couldn't find this in Ruud's list in the Solving Sudoku Forum.
Could you give me a reference?
Thanks.
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Red Ed

Joined: 04 Nov 2006
Posts: 21
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PostPosted: Thu Jun 14, 2007 5:58 pm    Post subject: Reply with quote

BR nets, which I defined purely for theoretical interest, are defined in this post: (here).

gsf's "ternary monoids" theory was the inspiration for BR nets. I'll leave gsf to explain that.
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gsf

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PostPosted: Thu Jun 14, 2007 7:10 pm    Post subject: Reply with quote

Red Ed wrote:
BR nets, which I defined purely for theoretical interest, are defined in this post: (here).

gsf's "ternary monoids" theory was the inspiration for BR nets. I'll leave gsf to explain that.

the "ternary monoids" description is on the player's forum
the constraint methods in my solver are (tersely) described by the --man option
I can fill in any gaps you find in those
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PostPosted: Thu Jun 14, 2007 7:19 pm    Post subject: Reply with quote

[delete]

Last edited by gsf on Thu Jun 14, 2007 7:48 pm; edited 1 time in total
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berthier

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PostPosted: Mon Jun 18, 2007 8:36 am    Post subject: Re: New book "The Hidden Logic of Sudoku" Reply with quote

After several people asked for more information on the content, I put some excerpt on my Web pages (http://www.carva.org/denis.berthier)
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berthier

Joined: 13 Jun 2007
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PostPosted: Thu Jun 21, 2007 2:52 pm    Post subject: Extended Sudoku board Reply with quote

As a complement to the book, and in order to make my resolution method easier to apply, I have devised an extended Sudoku Board, whith the two additional rn- and cn- spaces.
You can download it for free either on my Web pages or on the publisher's site:
http://stores.lulu.com/berthier
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vittyken

Joined: 14 Oct 2007
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Location: Clearwater, FL

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PostPosted: Sun Oct 14, 2007 11:18 am    Post subject: Re: New book "The Hidden Logic of Sudoku" Reply with quote

[quote="berthier"]This is to announce to this forum that I have just published a new book "The Hidden Logic of Sudoku", which may be of interest to some of you.]

I just got the book through Amazon yesterday and I read the prologue and the introduction.
I will admit I haven't read, in my estimation, a college level book in some time.
But from what I understand I will be using it to help me solve the most difficult Sudoku around.
What I am interested in knowing is will the book help explain a lot better the advanced situations of the xy-wing and higher than does some other Websites try to do? You wrote that the rules will be first in plain English and then it will go into the technical jargon: logic formulas with expressions.
I've read most of Hofstadter's GEB and can relate to the "strange loops" one can get into when doing a Sudoku puzzle.
Thank you for writing this book.
On a curious note, how long did it take you to write this? You first saw a Sudoku puzzle in Dec 2005 and published this book in 2007. Very impressive.
Thanks again.
Ken
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berthier

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PostPosted: Sun Oct 14, 2007 1:55 pm    Post subject: Re: New book "The Hidden Logic of Sudoku" Reply with quote

vittyken wrote:
On a curious note, how long did it take you to write this? You first saw a Sudoku puzzle in Dec 2005 and published this book in 2007. Very impressive.
Thanks again.
Ken


Thanks for your remarks.
I tried to introduce all the necssary logical background. If you have problems with chapters III and IV, you can skip them on a first reading and read the simple examples in the following chapters.

It took me about one year to write this book and SudoRules.
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vittyken

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PostPosted: Wed Oct 24, 2007 5:31 am    Post subject: programming a spreadsheet Reply with quote

On page 36, you said it "is an easy exercise to program a spreadsheet for computing the three new grids and their canditates...".
Is there an easy program?
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vittyken

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PostPosted: Tue Nov 20, 2007 1:08 pm    Post subject: Re: New book "The Hidden Logic of Sudoku" Reply with quote

berthier wrote:
vittyken wrote:
On a curious note, how long did it take you to write this? You first saw a Sudoku puzzle in Dec 2005 and published this book in 2007. Very impressive.
Thanks again.
Ken


Thanks for your remarks.
I tried to introduce all the necssary logical background. If you have problems with chapters III and IV, you can skip them on a first reading and read the simple examples in the following chapters.

It took me about one year to write this book and SudoRules.


On page 36 you mentioned it would be easy to program a spreadsheet to do the alternative grids, row-number, column-number.
Do you, or anybody else who is reading this, have one?
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Ruud
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PostPosted: Wed Nov 21, 2007 12:22 am    Post subject: Reply with quote

I have built RN and CN views into SudoCue. You can find more details in my release notes.

Ruud
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vittyken

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PostPosted: Wed Nov 21, 2007 5:40 am    Post subject: SudoCue Reply with quote

In a word, WOW!
It always makes me happy when a little programming knowledge solves a problem or follows a process.
I am flabergasted when a lot of programming knowledge does something like what you did.
Thanks a lot.
The next thing I am looking for is how to create a sudoku puzzle manually.
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